Repair method of repair target portion, repaired product, and repair apparatus

ABSTRACT

The present invention sufficiently heats a repairing material while preventing change in quality of a base material provided with the repairing material so as to securely bond the repairing material to a repair target portion. The repair method of the present invention, in order to repair a repair target portion  14  existing in an outer panel  1 , includes: a repairing material disposing step of disposing a repairing patch  21  including a resistance heating element  23  and a carbon fiber reinforced resin, and an adhesive  22 A including a thermosetting resin before being hardened for bonding the repairing patch  21  on the repair target portion  14 ; and a heating-hardening step of heating and hardening the thermosetting resin of the adhesive  22 A by causing the resistance heating element  23  to generate heat through supply of electricity thereto.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a division of prior U.S. application Ser. No. 14/227,171 filedMar. 27, 2014, now U.S. Pat. No. 10,065,727, which claims priority ofJapanese Application No. 2013-69373 filed Mar. 28, 2013. The content ofeach these applications is incorporated by reference herein in itsentirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a method of repairing a repair targetportion existing in a repair target, a repaired product, and a repairapparatus.

Description of the Related Art

An outer panel (skin) forming an outer surface of a fuselage and a wingof an aircraft requires repairing if the outer panel is damaged by alightning strike or flying objects such as hailstones. As a repairingmaterial for use in such repairing, a composite material, such as fiberreinforced plastic (FRP), is used.

In order to heat and harden the repairing material so as to bond thisrepairing material to the repair target portion, a heater mat is used,as shown in Japanese Patent Laid-Open No. 2009-208301. The heater mat isplaced on the repairing material disposed to the repair target portion.A heat gun or an oven may also be used for heating the repairingmaterial.

An external heat source, such as a heater mat, is used for heating therepairing material to transfer heat from the heat source to therepairing material. At this time, heat is diffused from the heat sourceand the repairing material to the surroundings of the repairingmaterial. Consequently, a base material (outer panel) where therepairing material is disposed may be changed in quality due tooverheating.

If output of the external heat source is decreased in order to avoidchange in quality of the base material, insufficient heating is appliedto the repairing material, which results in poor hardening, and hinderssecure bonding of the repairing material to the repair target portion.

An object of the present invention, which has been made in order tosolve the problems according to the conventional art, is to sufficientlyheat a repairing material while preventing change in quality of a basematerial provided with the repairing material so as to securely bond therepairing material to the repair target portion.

SUMMARY OF THE INVENTION

The present invention is a method of repairing a repair target portionexisting in a repair target, and includes: a repairing materialdisposing step of disposing a repairing material, which includes aresistance heating element and a thermosetting resin before beinghardened, on the repair target portion; and a heating-hardening step ofheating and hardening the thermosetting resin by causing the resistanceheating element to generate heat through supply of electricity thereto.

“Before being hardened” in the present invention is defined as a statein which the hardening does not yet have a predetermined hardness.

In the present invention, since the repairing material includes theresistance heating element, the repairing material generates heat so asto heat itself through supply of electricity to the resistance heatingelement without using an external heat source.

Thermal energy generated by the resistance heating element isefficiently transferred to the thermosetting resin also included in therepairing material. The resistance heating element is caused to generateheat with sufficient quantity of heat for hardening the thermosettingresin, thereby sufficiently heating the repairing material whileminimizing thermal diffusion to the surroundings of the repairingmaterial.

According to the present invention, it is possible to securely bond therepairing material to the repair target portion of the base materialthrough completion of hardening of the thermosetting resin at apredetermined hardness while preventing change in quality of the basematerial provided with the repairing material due to overheating.

The repairing material used in the present invention includes variousforms.

The repair method using a composite material in the repairing materialincludes: a method of laminating fibers, which is formed in a sheet formand impregnated with liquid thermosetting resin, to the repair targetportion, and hardening the resin by heating (wet lay-up); and a methodof laminating a half-cured intermediate material (prepreg) to the repairtarget portion, and hardening this material by heating. The above repairmethod may also include such a method that uses a repairing patch heatedand hardened in advance (precured patch), and bonds this repairing patchto the repair target portion with a thermosetting adhesive.

Hence, the repairing material is equivalent to a precured patch formedof a thermosetting resin hardened in advance, and a thermosettingadhesive that bonds the precured patch to the repair target portion, forexample.

As another form of the repairing material, the repairing material isequivalent to prepreg formed of a half-hardened thermosetting resin, anda thermosetting adhesive that bonds the prepreg to the repair targetportion.

As yet another form of the repairing material, the repairing material isequivalent to a liquid thermosetting resin and fibers in the case ofperforming the wet lay-up.

It is defined that the repair target portion provided with the abovedescribed various repairing materials includes a damaged portiongenerated in the repair target by impact, high temperature, abrasion,and corrosion, etc., and a predetermined range surrounding this damagedportion.

In the repair method of the present invention, the repairing materialmay be configured to include: a carbon fiber reinforced resin includinga thermosetting resin; and an insulator for insulating the resistanceheating element from the carbon fiber reinforced resin.

This configuration prevents the resistance heating element from beingshort-circuited to the carbon fibers, and thus the present invention isalso applicable to a repairing material formed of a carbon fiberreinforced resin.

In the repair method of the present invention, if the repairing materialis configured to include: a first repairing material formed of a fiberreinforced resin including the thermosetting resin; and a secondrepairing material including the thermosetting resin, and bonding thefirst repairing material to the repair target portion, the resistanceheating element may be included in at least one of the first repairingmaterial and the second repairing material.

The first repairing material is equivalent to a repairing patch andprepreg, for example. The second repairing material is equivalent to anadhesive for bonding the repairing patch or the prepreg to the repairtarget portion. If the resistance heating element is included in atleast one of the first repairing material and the second repairingmaterial, the entire repairing material is heated with heat generated bythis resistance heating element; therefore, it is possible tosufficiently harden both the thermosetting resin included in the firstrepairing material and the thermosetting resin included in the secondrepairing material.

The repair method of the present invention is suitable for repairing ahoneycomb core sandwich structural body configured by holding a corehaving a honeycomb structure that includes a number of cells betweenouter skins.

Moisture is accumulated inside the core of the honeycomb core sandwichstructural body. If the repairing material is heated, the inner pressureof the cells is increased due to vaporized moisture inside the corebecause of increase in temperature of the core, and thus the honeycombcore sandwich structural body may be destroyed.

According to the present invention, however, it is possible to minimizethermal diffusion to the surroundings of the repairing material, asdescribed above, thereby suppressing vaporization of the moisture insidethe core. Accordingly, it is possible to eliminate a drying processinside the core that has been required in the conventional art,resulting in reduction of time required for repairing the honeycomb coresandwich structural body.

The present invention is a method of repairing a repair target portionexisting in a repair target, and the method includes: a repairingmaterial disposing step of disposing a repairing material, whichincludes a resistance heating element and a thermoplastic resin, on therepair target portion; and a step of heating and melting thethermoplastic resin by causing the resistance heating element togenerate heat through supply of electricity to the resistance heatingelement, and thereafter putting the thermoplastic resin into asolidified state.

In the present invention, because the resistance heating element isincluded in the repairing material, the repairing material generatesheat so as to heat itself by supplying electricity to the resistanceheating element without using an external heat source.

The thermal energy generated by the resistance heating element isefficiently transferred to the thermoplastic resin also included in therepairing material. Accordingly, the resistance heating element iscaused to generate heat with quantity of heat sufficient for melting thethermoplastic resin, thereby sufficiently heating and melting therepairing material while minimizing thermal diffusion to thesurroundings of the repairing material.

Hence, according to the present invention, it is possible to securelybond the repairing material to the base material through melting andsubsequent hardening of the thermoplastic resin by heating withoutchanging the quality of the base material provided with the repairingmaterial due to overheating.

The present invention may also be developed to a repaired product.

A repaired product of the present invention is produced such that arepairing material including a resistance heating element and athermosetting resin or a thermoplastic resin is firmly bonded to arepair target portion.

The present invention may be suitably applicable to components includedin an aircraft. In this case, the repair target portion exists in acomponent included in the aircraft.

The present invention may also be developed to a repair apparatus.

A repair apparatus for a repair target portion of the present inventionis a repair apparatus of repairing a repair target portion existing in arepair target, and the apparatus includes: a repairing material thatincludes a resistance heating element and a thermosetting resin or athermoplastic resin, and is disposed on the repair target portion; and apower source for supplying current to the resistance heating element soas to heat the thermosetting resin or the thermoplastic resin.

According to the present invention, it is possible to sufficiently heatthe repairing material while preventing change in quality of the basematerial, thereby securely bonding the repairing material to the repairtarget portion of the base material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view schematically showing an outer panelrepaired by a repair method of the present embodiment;

FIG. 2A is a plan view of a repairing patch according to the presentembodiment;

FIG. 2B is a cross sectional view of the repairing patch according to avariation of the present embodiment;

FIG. 2C is a plan view of the repairing patch of this variation;

FIG. 3A is a drawing explaining a procedure of a repairing method of thepresent embodiment; and

FIG. 3B is a drawing explaining the procedure of the repair method ofthe present embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention will be described in detail based onembodiments shown in accompanying drawings.

First, a configuration of an outer panel of an aircraft obtained byrepairing will be described.

The outer panel 1 shown in FIG. 1 forms an outer surface of a wing ofthe aircraft. The outer panel 1, not shown, is respectively disposed onupper and lower sides of the wing with a distance therebetween, and theouter panel 1 along with spars that form a front edge and a rear edge ofthe wing are assembled in a box shape.

This outer panel 1 has such a structure that holds a core (core member)10 having a honeycomb structure between a couple of outer skins 11, 12(honeycomb core sandwich structural body). The outer panel 1 may includeother layers than the core 10 and the outer skins 11, 12.

The outer panel 1 may constitute the outer surface of a fuselage of theaircraft.

The core 10 includes bulkheads 10A that form a number of cells 13 eachhaving a hexagon cross section. The core 10 is made of a compositematerial, a metallic material, or a resin material, etc.

The core 10 has a hollow space inside each cell 13, and thus includesair thereinside. Moisture is contained in the air. The moisture is alsoheld in each bulkhead 10A. Water droplets may be produced on thesurfaces of the bulkheads 10A by dew condensation. Hence, the moistureis accumulated inside the core 10 (inside the cells 13 and on thebulkheads 10A).

The outer skins 11, 12 are made of a composite material, a metallicmaterial, or a resin material, and are fixed to the end surfaces of thecore 10. The outer skins 11, 12 cover openings surrounded by thebulkheads 10A so as to seal the cells 13.

The outer panel 1 may be damaged by receiving impact of a lightningstrike or a hailstorm. Such damage may generate a repair target portion14 required to be repaired in the outer panel 1.

The repair target portion 14 is generated such that a flying object,such as a hailstone, penetrates the outer skin 11, and reaches theinside of the core 10. A damage hole 141 is formed through the outerskin 11 in the thickness direction of the outer skin 11. A damage recess142 continued to the damage hole 141 is formed in the core 10.

The repair target portion 14 denotes a damaged portion that is an innersurface of the damage hole 141 and the damage recess 142, and apredetermined area including the surroundings of the damaged portion.

If the damage hole 141 is formed, rain water and rinse water mayinfiltrate into the core 10 through the damage hole 141, whichfacilitates moisture accumulation inside the core 10.

In the present embodiment, the damage hole 141 is covered with aplate-like repairing patch 21 (first repairing material) formed of acarbon fiber reinforcement resin, and the repairing patch 21 is bondedto the surroundings of the damage hole 141.

The outer skin 11 around the damage hole 141 preferably has a surfaceprepared to be suitable for being bonded to the repairing patch 21through sanding and rinse.

In the present embodiment, the damage recess 142 is left as a cavitywith filling nothing therein, but the damage recess 142 may be filledwith a material for repairing.

The repairing patch 21 is produced by laminating carbon fibers formed ina sheet form, impregnating thermosetting resin, such as epoxy,polyimide, polyurethane, and unsaturated polyester, in the laminatedmaterial, and heating this thermosetting resin to be hardened. Therepairing patch 21 may be a precured patch that is cured in advancebefore the repairing.

A conductive lightning protection material formed in a sheet form may belaminated onto the repairing patch 21.

The repairing patch 21 includes a linear resistance heating element 23,and an insulation film 24 covering the outer circumference of theresistance heating element 23 (FIG. 2A), in addition to the carbonfibers and the thermosetting resin.

The resistance heating element 23 is formed of a material having largeresistivity, such as an alloy of nickel and chrome (nichrome), an alloyof iron and chrome, and an alloy of iron, chrome, aluminum, and cobalt,and the resistance heating element 23 generates heat when current issupplied thereto. The resistance heating element 23 is disposed in aserpentine manner in the in-surface of the repairing patch 21, as shownin FIG. 2A.

The insulation film 24 is an insulator formed of an insulation resin,and insulates the resistance heating element 23 from the carbon fibersincluded in the repairing patch 21. This configuration prevents theresistance heating element 23 from being short-circuited to the carbonfibers.

The resistance heating element 23 and the insulation film 24 are soembedded in the repairing patch 21 as to be disposed between thelaminated carbon fiber sheets at the time of producing the repairingpatch 21.

Other fibers than the carbon fibers, such as glass fibers, may also beused in the repairing patch 21. The resistance heating element 23 havingno insulation film 24 therearound may be directly embedded in areinforced resin using glass fibers, which is an insulator.

An adhesive layer 22 (second repairing material) formed of athermosetting resin is disposed between the repairing patch 21 and theouter skin 11. The adhesive layer 22 along with the repairing patch 21are included in the repairing material 20.

The thermosetting resin used in the adhesive layer 22 may be the same asor different from the thermosetting resin used in the repairing patch21.

Hereinafter, the repair method of the outer panel 1 will be describedwith reference to FIGS. 3A and 3B.

As shown in FIG. 3A, a thermosetting adhesive 22A formed in a film form,and the repairing patch 21 are disposed on the outer skin 11 around thedamage hole 141 (repairing patch disposing step).

The adhesive 22A may be formed in the same shape as that of therepairing patch 21 as shown in the drawing, or may be formed in anannular shape around the damage hole 141.

As shown in FIG. 3B, the repairing patch 21 and its surroundings arecovered with a thermal resistant bag film 41, and a clearance betweenthe bag film 41 and the outer skin 11 is sealed. Vacuum evacuation isthen performed through a valve (not shown) provided on the bag film 41(vacuum evacuating step). It is preferable to continue the vacuumevacuation even in the subsequent heating-hardening step.

Because of a difference in pressure of the atmosphere between the insideand the outside of the bag film 41 that is depressurized by the vacuumevacuation, the repairing patch 21 is pressed against the surface of theouter skin 11, thereby allowing the repairing patch 21 to be in tightcontact with the outer skin 11 through the adhesive 22A.

Subsequently, the resistance heating element 23 included in therepairing patch 21 is connected to a power source 15. Current issupplied from the power source 15 to the resistance heating element 23so as to cause the resistance heating element 23 to generate heat. Then,thermal energy generated by the resistance heating element 23 istransferred to the thermosetting resin included in the adhesive 22Aimmediately under the repairing patch 21, and thus the thermosettingresin of the adhesive 22A is hardened (heating-hardening step).

After being hardened, the adhesive 22A firmly adheres to the repairingpatch 21 and the outer skin 11 so as to form the adhesive layer 22. Therepairing patch 21 is integrally bonded to the outer panel 1 through theadhesive layer 22.

In this manner, the repairing of the outer panel 1 is completed.

According to the repair method of the present embodiment, the repairingpatch 21, which is included in the repairing material 20 along with theadhesive 22A, includes therein the resistance heating element 23functioning as a heat source; thus, it is possible to cause therepairing material 20 required to be heated to generate heat for heatingitself without using an external heat source.

In the present embodiment, where the heat source and the heating targetare identical, different from the case of using the external heatsource, it is not required to generate thermal energy with greaterquantity of heat than quantity of heat reaching the repairing material20 that is the heating target, estimating diffusion of the thermalenergy during transmission of the heat.

Specifically, in the present embodiment, the resistance heating element23 is caused to generate heat with quantity of heat sufficient forhardening the adhesive 22A, thereby sufficiently heating the adhesive22A as well as minimizing thermal diffusion to the surroundings of therepairing patch 21 and the adhesive 22A.

According to the present embodiment, it is possible to securely bond therepairing patch 21 to the outer skin 11 while preventing change inquality of the outer skin 11 that is the base material provided with therepairing patch 21 due to overheating.

Rigidity of the resistance heating element 23 enhances rigidity of therepairing patch 21, thereby securing sufficient strength of the repairedouter panel 1.

In addition, according to the present embodiment, simply by disposingthe repairing material 20 on the repair target portion 14, andconnecting the power source 15 to the resistance heating element 23incorporated in the repairing material 20, preparation for heating thethermosetting resin is completed, so that it is unnecessary to dispose aheater mat on the repairing material 20, and to convey the outer panel 1and house this in an oven. The power source 15 is only required to beconnected to the resistance heating element 23, and thus the powersource 15 is unnecessary to be placed close to the outer panel 1.Because the power source 15 is smaller than the heater mat or the ovenin size, it is easy to install the power source 15 even in a small-scaleairport. Accordingly, the repair method of the present embodiment isfeasible in any local airport.

If the core 10 is heated at the time of heating and hardening theadhesive 22A, the temperature inside the core 10 becomes increased, andmoisture accumulated inside the core 10 becomes vaporized. The openingof each cell 13 is sealed by the outer skins 11, 12, so that thepressure inside the cells 13 becomes so increased due to thevaporization that a force of peeling off the outer skins 11, 12 from thecore 10 is applied to the outer panel 1. A pin hole for releasing watervapor inside the core 10 is formed in the repairing patch 21 in somecases, but if the inner pressure of the cells 13 becomes increased, theouter skins 11, 12 may be peeled off from the core 10.

In the present embodiment, however, it is sufficient for the resistanceheating element 23 incorporated in the repairing material 20 to generatequantity of heat to be absorbed by the repairing patch 21 and theadhesive 22A, and thus it is possible to restrict the area to be heatedwithin the repairing patch 21 and the adhesive 22A. Accordingly, it ispossible to prevent increase in temperature inside the core 10, therebypreventing destruction of the outer panel 1 caused by increase of theinner pressure of the cells 13.

Accordingly, a process of drying the core 10 in advance for preventingdestruction of the outer panel 1 can be eliminated. It takes a very longtime to sufficiently dry the core 10 where moisture is contained in theair existing in a number of the cells 13 and in the bulkheads 10A;therefore, the repair method of the present embodiment that eliminatesthe drying process can significantly reduce time required for therepairing.

Accordingly, the repair method of the present embodiment is suitable forrepairing of the outer panel 1 of an aircraft where a scheduled flightservice is strongly desired.

Because the resistance heating element 23 of the present embodiment isso disposed in a serpentine manner as to be distributed in thein-surface direction of the repairing patch 21, it is possible to causethe repairing patch 21 to uniformly generate heat across the entireplane thereof.

If the repairing patch 21 is thick, the resistance heating element 23may be distributed in the thickness direction, thereby allowing therepairing patch 21 to uniformly generate heat across its entirethickness.

The resistance heating element 23 may be formed of any kind of material.For example, a metallic resistance element, such as molybdenum,tungsten, platinum, and molybdenum disilicide, or a non-metallicresistance element, such as silicon carbide, graphite, zirconia, andlanthanum chromite, may be used in the resistance heating element 23.

In the aforementioned embodiment, the resistance heating element 23 isincluded in the repairing patch 21, and the resistance heating element23 may also be included in the adhesive 22A. The adhesive 22A includingthe resistance heating element 23 may be produced by embedding theresistance heating element 23 in the base material of the adhesive 22A.If the base material of the adhesive 22A is formed of an insulationresin, the resistance heating element 23 is insulated by the insulationresin, and thus it is unnecessary to provide the resistance heatingelement 23 with the insulation film 24.

If the resistance heating element 23 is included in the adhesive 22A,the repairing material 20 generates heat by itself in the same manner asmentioned above; therefore, it is possible to sufficiently heat theadhesive 22A while preventing change in quality of the base material dueto overheating.

The resistance heating element 23 may be included in both the repairingpatch 21 and the adhesive 22A.

In the above embodiment, the resistance heating element 23 is insulatedfrom the carbon fibers by the insulation film 24, but the resistanceheating element 23 may be insulated using any configuration.

The repairing patch 25 shown in FIG. 2B includes a first CFRP layer 26formed of a carbon fiber reinforced resin, a heating layer 27 includingthe resistance heating element 23 and an insulation resin 29, and asecond CFRP layer 28 having the same configuration as that of the firstCFRP layer 26.

The first CFRP layer 26, the heating layer 27, and the second CFRP layer28 are laminated in this order so as to adhere to one another.

The first CFRP layer 26 and the second CFRP layer 28 are produced byheating and hardening carbon fibers impregnated with a thermosettingresin.

The heating layer 27 is produced by forming the resistance heatingelement 23 embedded in the insulation resin 29 into a sheet form. Theinsulation resin 29 insulates the resistance heating element 23 from thecarbon fibers included in both the first CFRP layer 26 and the secondCFRP layer 28. Hence, the resistance heating element 23 is embedded inthe insulation resin 29 without being provided with the insulation film24, as shown in FIG. 2C.

The resistance heating element 23 is also included in the repairingpatch 25, and thus it is possible to attain the same operation andeffect as those described in the present embodiment.

Prepreg may also be used in the repairing material disposed on therepair target portion 14. The resistance heating element 23 is disposedbetween the laminated carbon fibers of prepreg. If necessary, theresistance heating element 23 is also embedded in a film-like adhesivefor bonding the prepreg to the repair target portion 14. This prepregand the adhesive are included in the repairing material.

The adhesive and the prepreg are disposed on the repair target portion14, and the thermosetting resin included in both the adhesive and theprepreg are heated and hardened by supplying electricity to theresistance heating element 23.

A fiber thermosetting resin or a liquid thermosetting resin may also beused as the repairing material. The resistance heating element 23 isdisposed between the fibers laminated to the repair target portion 14.The thermosetting resin impregnated in the fibers is heated and hardenedthrough supply of electricity to the resistance heating element 23.

A thermoplastic resin, such as nylon, polyethylene, polystyrene, andpolyvinyl chloride, may also be used in the repairing material.

For example, in the case of using such a repairing material in which theresistance heating element 23 is embedded in prepreg produced byhalf-hardening fibers impregnated with the thermoplastic resin, arepairing material disposing step of disposing this repairing materialon the repair target portion 14, and a step of causing the resistanceheating element 23 to generate heat through supply of electricitythereto, thereby heating and melting the thermoplastic resin, andthereafter putting this thermoplastic resin into a solidified state areperformed. In this case, as similar to the case of using thethermosetting resin, the repairing material generates heat by itselfbecause the repairing material includes the resistance heating element23, and thus it is possible to sufficiently heat and melt thethermoplastic resin without changing the quality of the base material.After the thermoplastic resin is melted, supply of electricity to theresistance heating element 23 is stopped, and the thermoplastic resin isheld for a predetermined time so that the thermoplastic resin becomessolidified, thereby allowing the repairing material to firmly adhere tothe repair target portion 14.

The outer panel 1 is not limited to the honeycomb core sandwichstructural body, and may be configured in any form. For example, anouter panel formed of a fiber reinforced resin across its entirethickness, or even a metallic outer panel may also be the repair target.

The repair method of the present invention is applicable to repairing ofnot only the outer panel of an aircraft, but also wall materials, floormaterials, ceiling materials, and doors included in an aircraft.

The present invention may be applicable to repairing of other structuralcomponents and accessories of an aircraft.

In addition, the present invention may be applicable to any repairtarget other than components included in an aircraft, such as blades ofa windmill, and also applicable to repairing of various objects damagedby impact, high temperature, abrasion, and corrosion, etc.

The repair target in the present invention is not limited to aplate-like object. The present invention may be widely applicable torepairing of bonding the repairing material to the repair target portionexisting in an object in any form.

Other than the above description, the configurations of theaforementioned embodiments may be appropriately selected, or changed toother configurations without departing from the spirit and scope of thepresent invention.

What is claimed is:
 1. A method of repairing a repair target portionexisting in a repair target, the method comprising: a repairing materialdisposing step of disposing a repairing material, which includes aresistance heating element and a thermoplastic resin, on the repairtarget portion; and a step of heating and melting the thermoplasticresin by causing the resistance heating element to generate heat throughsupply of electricity to the resistance heating element, and thereafterputting the thermoplastic resin into a solidified state, wherein therepairing material comprises: a carbon fiber reinforced resin includingthe thermoplastic resin and carbon fibers; and an insulator forinsulating the resistance heating element from the carbon fibers.
 2. Themethod of repairing a repair target portion according to claim 1,wherein a honeycomb core sandwich structure configured by holding a corehaving a honeycomb structure including a number of cells between outerskins is repaired as the repair target.
 3. The method of repairing arepair target portion according to claim 1, wherein the resistanceheating element is embedded in the repairing material prior to therepairing material disposing step.
 4. The method of repairing a repairtarget portion according to claim 1, wherein the resistance heatingelement and the insulator are embedded in the repairing material priorto the repairing material disposing step.
 5. The method of repairing arepair target portion according to claim 1, wherein the resistanceheating element is disposed in a meandering manner in an in-surface ofthe repairing material.
 6. The method of repairing a repair targetportion according to claim 1, wherein the resistance heating element isdistributed in a thickness direction of the repairing material.
 7. Arepair apparatus of repairing the repair target portion existing in therepair target according to claim 1, the repair apparatus comprising: therepairing material; and a power source for supplying current to theresistance heating element so as to heat the thermoplastic resin.